Grease gun or the like



May 26, 1931. B. J. MAHONEY GREASE GUN on THE LIKE Filed Sept. 19. 1928 filwnfm" Wf M I .ilmwey MN NW. .N MM. N k.

Patented May 26, 1931 UNITED STATES PATENT oFFme BURTON J. MAHONEY, OF CHICAGO, ILLINOIS, ASSIGNOR TO HOFFMAN'N HIGfi PRESSURE EQUIPMENT COMPANY, A CORPORATION OF ILLINOIS GREASE GUN OR THE LIKE.

Application filed September 19, 1928. Serial No. 806,888.

The present invention has for its object to produce a simple and novel device in which d oil, grease or other liquid or semi-liquid ma terial may be stored and from which it may be 5 discharged at will under great pressure.

The various features ofnovelty whereby my invention is characterized will hereinafter be pointed out with particularity in the claims; but, for a full understanding of my invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with.

the accompanying drawings, wherein:

ranged in accordance with myinvention; and Fig. 2 is a central longitudinal section.

My improved device comprises a closed barrel the interior of which is divided into two chambersby a transverse partition. In one chamber is contained the liquid or semiliquid material, and in the other chamber is a piston for operating a plunger of small diameter and discharging measured quan-. tities of the material. The plunger operates in a tube extending through the chamber containing the liquid or semi-liquid material and having therein a port to admit the material. In accordance with my invention air under pressure is admitted behind the piston and upon the body of the liquid or semi-liquid material by the-operation of a single valve. Consequently the material will be delivered to the plunger under pressure and will then be discharged by the plunger at a much higher pressure.

In the particular arrangement shown in the drawings, the barrel or casing consists of two cylindrical parts 1 and 2 each screwed thick casting. The ends of the members 1 at one end upon a head 3 in the form of a preferably placed at evice.

In the chamber 7 is a piston 9 provided with a long stem 10 fitting slidably into the tube 6 and constituting an ejecting plunger. The stem or plunger is of such a length that when the piston is near the end. wall 4, the free end of the same or plunger lies at some distance inwardly from the opposite end wall 5. There is a strong spring 11 between the the long axis of the piston and the transverse partition 3 for the purpose of moving the piston toward the end wall 4 when free to do so. The part 2 is pro.- Figure 1 is a side view of the device arthe tube through the port 15 and out into a discharge conduit 16 forming a continuation of the tube. If, pressure is applied to the'piston 14 in a direction tending to ,move it toward the end wall 5, the pressure will be transmitted to the fluid so as to cause the latter to be forced through the port into the tube. Then, if pressure is applied to the piston 9, the plunger will be forced into the tube until it closes the port 15 and then forces the fluid in advance thereof through the conduit.

vA handle 17 is secured to and projects from one side of the casing. The handle may conveniently be screwed to a heavy boss 13 integral with and projecting from the head or partition 3, on the underside of the barrel.

valve device inwardly against the resistance of the spring. The parts are so proportioned and arranged that the inner end of the valve device normally forms a seal cutting off communication between the ends of the passage 18, whereas the outer end of the valve device leaves the corresponding end of the passage open to atmosphere. Then the trigger is pressed, the outer end of the valve device closes the corresponding end of the passage, whereas the inner end of the valve device moves into a position that permits communication between the two ends of the passage to be established. An air pipe 23 extends up through the handle and opens into that portion of the passage 18 in which the spring lies. A branch passage 24 extends from the other half or section of the passage 18 up to the partition member 3. In the partition 3 is a passage 25 communicating at one end with the passage 24 and opening out through the side of the partition member into the chamber 8. The opening in the chamber 8 is normally closed by a small spring-held check valve 26. A pipe or conduit 27 extends from a point in the chamber 7 behind the piston 9 to the inner end of the handle where it communicates with a passage 28 branching from the passage 24.

In the outlet conduit 16 from the device is a check valve 30 seating toward the fluid reservoir and held in position by a strong spring 31.

Assuming the parts to be in the positions illustrated in Fig. 2, the fluid reservoir to be full and the pipe 23 to be connected to a source of compressed air, it will be seen that if the trigger is pressed air will enter both the chamber 7 and the chalnber 8, behind the respective pistons. Thus the piston 14. will be caused to exert a pressure on the fluid to force the same through the port. 15. pressure is preferably not great enough to unseat the check valve 30. hen the pressure behind the piston 9 has been built up, it will be forced toward the right, causing the plunger to move forward and drive the fluid ahead of it out through the conduit. As soon as the end of the plunger passes the port 15 the fluid in advance of the same is constrained sure, opening the check valve 30. After the to move ahead and does so under great prespiston 9 has completed its working stroke the trigger is released, permitting the air behind this piston to escape to atmosphere through the pipe 27 and the valve device in the handle. The spring then returns the piston to its normal idle position and another charge of fluid will flow through the port 15 into the tube. It will be seen that the check valve 26 prevents the escape of air from behind the piston 14, so that the air introduced into the chamber 8 remains and insures that there will be pressure on the fluid to force it into the tube as soon as the piston 9 has been retracted.

It may at times be necessary to hold the device by grasping it at the rear end. I have therefore provided a second trigger, having This a long arm 32 lying below the rear end of the casing and at a small angle thereto. The auxiliary trigger is L-shaped, and the short arm 33 is connected to the trigger 22 by a link 34. Therefore by pressing the trigger arm 32 against the barrel the controlling valve will be opened in the same way as though pressure were applied directly to the trigger 22.

If desired, some means may be placed in the discharge conduit, outwardly from the check valve 30, to relieve the pressure between the check valve and the discharge end. In the arrangement shown, the conduit has a section in the form of a valve casing 36 provided with a tubular neck 37 projecting from the side. A thumb screw 38 extends down into this neck and seals the same. However, the neck is provided with a port 39 through the side. Normally the screw covers the port 39, but, when it is unscrewed far enough, the port is opened and the pressure in the con duit outwardly from the check valve can be relieved through the same.

While I have illustrated and described with particularity only a single preferred form of my invention, I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claims.

I claim 1. In a device of the character described, a barrel containing a chamber for fluids and a second chamber, a piston in said second chamber, a tube extending from a point within the second chamber through the other chamber, a conduit connected to said tube, a plunger connected to said piston and fitting slidably, into said tube, a spring to retract the piston and plunger, said tube having a port therein at a point that is beyond the free end of the plunger a distance less than the stroke of the plunger when the latter is retracted, a handle on said device, said handle having a passage for compressed air, a manual valve in said passage, there being branch passages leading from the valve into the second chamber behind the piston and into the chamber for fluids, and an outwardly seated check valve in the passage leading to the chamber for fluids.

2. In a device of the character described, a barrel containing a chamber for fluids and a second chamber, a piston in said second chamber, a tube extending from a point within the second chamber through the other chamber, a conduit connected to said tube, a plunger connected to said piston and fitting slidably into said tube, a spring to retract the piston and plunger, said tube having a port therein at a point that is be 0nd the free end of the plunger a distance ess than the stroke of the plunger when the latter is retracted, means for simultaneously admitting compressed air behind the piston and into the chamber for fluids and afterwards exhausting the air from behind the piston, and a. check valve to retain the air in the chamber for fluids.

In testimony whereof, I sign this specification.

BURTON J. MAHONEY. 

